Rajpaul Attariwala transitioned from engineering to radiology because he wanted to apply his engineering background to create a unique MRI scanner capable of constructing whole-body images with unmatched resolution. He found that radiology, with its focus on technology and imaging, was the perfect field to combine his engineering skills with his interest in the human body and physiology.
An x-ray works by using high-energy wavelengths that penetrate the body. Dense structures like bones absorb the x-ray beam, appearing white on the film, while less dense structures like soft tissues and air allow the beam to pass through, appearing black. The main limitation is that x-rays provide a 2D image of 3D structures, leading to overlapping layers of tissue that can obscure details.
A T1 weighted MRI image highlights fat, making it appear bright and providing excellent anatomical detail. A T2 weighted image highlights water, making it appear bright, and is useful for detecting edema and other abnormalities where water content is increased. T2 images take longer to acquire due to the longer echo time required to capture both fat and water signals.
MRI is considered safer than CT scans because it does not use ionizing radiation, which can damage cells and DNA, potentially leading to cancer. MRI uses magnetic fields and radio waves to produce images, making it a radiation-free imaging tool.
The risks associated with cancer screening include false positives, where a test indicates cancer when it is not present. This can lead to unnecessary follow-up tests, biopsies, and emotional distress. False positives can result in overdiagnosis and overtreatment, which may carry their own risks and complications.
Diffusion-weighted imaging (DWI) in MRI works by measuring the movement of water molecules in tissues. It detects areas where water diffusion is restricted, which often indicates high cellular density, such as in tumors. DWI is particularly useful for detecting cancer because it can highlight areas of abnormal tissue that may be cancerous.
The Tesla rating in MRI machines indicates the strength of the magnetic field. Higher Tesla ratings (e.g., 3T) allow for better resolution and faster imaging but can also increase the risk of artifacts and heating. Lower Tesla ratings (e.g., 1.5T) provide good penetration and are often optimized for whole-body imaging without the drawbacks of higher fields.
Standardization in MRI technology is important because it ensures consistency and reliability in imaging results across different machines and facilities. Without standardization, the quality and interpretation of MRI scans can vary widely, leading to potential misdiagnoses and inconsistent patient care.
Potential advancements in MRI technology in the next 5-10 years include faster scanning times, improved resolution, and the integration of machine learning to enhance image analysis and diagnostic accuracy. Advances in computational power and software could also enable more sophisticated image processing and real-time analysis.
Machine learning impacts the field of radiology by assisting radiologists in analyzing images more efficiently and accurately. It can help in identifying patterns, detecting abnormalities, and even serving as a second reader to reduce the likelihood of missing critical findings. Machine learning can also aid in the analysis of longitudinal studies by comparing changes over time.
In this episode, radiologist/engineer, Raj Attariwala, explains how he was able to apply his engineering background to create a unique MRI scanner that is capable of constructing whole-body images with a resolution that is unmatched in the industry. Peter and Raj discuss the implications of such a robust, radiation-free imaging tool on the early detection of cancer. They dive deep into cancer screening and define terms such as sensitivity and specificity that are necessary to really understand this complex space. They then describe the biggest risks involved in this type of screening (false positives) and how Raj’s unique technology and process might drive down this risk substantially. But before that, they discuss all the common imaging technology from X-ray, to CT scan, to PET scans, to ultrasound, to MRI, and more. They touch on the history of each, how they work, the usefulness and limitations of each of them, as well as the varying risks involved such as radiation exposure. If you are interested in cancer screening and/or you’ve ever wondered how any radiology tool works, this episode is for you. We discuss: Raj’s road from engineering to radiology [7:45]; How X-ray works, the risk of radiation exposure, and the varying amounts of radiation associated with the different imaging technologies [18:00]; Computed tomography scans (CT scans): The history of CT, how it works, and why we use contrast [27:45]; Ultrasound: Benefits and limitations, and a special use for the heart [40:45]; Detecting breast cancer with mammography: When is works, when you need more testing, and defining ‘sensitivity’ and ‘specificity’ [51:15]; Magnetic resonance imaging (MRI): How it works, defining terms, and looking at the most common types of MRI [1:03:45]; Brain aneurysms: Using MRI to find them and save lives [1:23:45]; Raj’s unique MRI technology [1:30:00]; The risk of false positives in cancer detection, and how Raj’s MRI can reduce the number of false positives (i.e., increase specificity) [1:43:40]; The unique software Raj created to pair with his MRI machine [1:51:15]; Comparing the radiation exposure of a whole-body PET-CT to Raj’s equipment (DWIBS-MRI) [1:53:40]; How diffusion-weighted magnetic resonance imaging (DW-MRI) has revolutionized cancer screening [1:55:15]; Why a DW-MRI is still not a perfect test [1:59:00]; The potential for advancing MRI technology: Where does Raj think it could improve in the next 5-10 years? [2:03:00]; Are there any commercially available scanners that can match the resolution of Raj’s images? [2:06:00]; Machine learning: When and where might machine learning/AI impact the field of radiology? [2:08:40]; and More.
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